A Practical Guide to Supramolecular Chemistry, Wiley, Chichester, 2005;
(g) P. D. Beer, P. A. Gale and D. K. Smith, Supramolecular Chemistry,
Oxford University Press, 1999; (h) F. Vo¨gtle, Supramolecular Chemistry
– An Introduction, Wiley, New York, 1991.
2 B. Alberts, A. Johnson, J. Lewis, M. Raff, K. Roberts and P. Walter,
Molecular Biology of the Cell, Garland Science, Taylor & Francis
Group, New York, 4th edn, 2002, p. 134.
3 (a) V. Berl, I. Huc, R. Khoury and J.-M. Lehn, Chem.–Eur. J., 2001, 7,
2798; (b) V. Berl, I. Huc, R. Khoury and J.-M. Lehn, Chem.–Eur. J.,
2001, 7, 2810; (c) for structural changes induced by solvent effects, see:
D. J. Hill and J. S. Moore, Proc. Natl. Acad. Sci. U. S. A., 2002, 99,
5053.
4 P. N. W. Baxter, R. G. Khoury, J.-M. Lehn, G. Baum and D. Fenske,
Chem.–Eur. J., 2000, 6, 4140.
5 G. Baum, E. C. Constable, D. Fenske, C. E. Housecroft and T. Kulke,
Chem. Commun., 1998, 2659.
6 A. S. Lane, D. A. Leigh and A. Murphy, J. Am. Chem. Soc., 1997, 119,
11092.
7 O. Mamula, M. Lama, H. Stoeckli-Evans and S. Shova, Angew. Chem.,
Int. Ed., 2006, 45, 4940.
8 (a) J.-M. Lehn, Chem.–Eur. J., 1999, 5, 2455; (b) P. T. Corbett,
J. Leclaire, L. Vial, K. R. West, J.-L. Wietor, J. K. M. Sanders and
S. Otto, Chem. Rev., 2006, 106, 3652.
Fig. 3 1H NMR spectra (400 MHz, CD3CN) for the possible
mechanism for amine mediated conversion of grid [Co414]8+ into the
pincer [Co(CH3CN)21]2+ passing through the amine-coordinated pincer
intermediate [Co(nPrNH2)21]2+
.
[Co(DMSO)6(BF4)2],14 in CD3NO2 led only to the pincer-like
complex, presumably due to the coordination of DMSO molecules
to the cobalt centre. Thus, the presence of accessible axial sites in
the pincer complex but not in the grid species offers another handle
on controlling the system.
To summarize, the couple [Co414]8+/[Co(CH3CN)21]2+ repre-
sents a system of two solvent-interconvertible paramagnetic Co(II)
complexes and implements three features: (i) adaptation to
external/medium effects, (ii) dual ligand structural plasticity and
(iii) effector-induced facilitation of structural interconversion.
Further investigations concerning the behaviour of other metal
ions and of related systems presenting constitutional dynamic
behaviour are ongoing.
9 (a) J.-M. Lehn, Proc. Natl. Acad. Sci. U. S. A., 2002, 99, 4763; (b)
J.-M. Lehn, Prog. Polym. Sci., 2005, 30, 814.
10 (a) G. S. Hanan, D. Volkmer, U. S. Schubert, J.-M. Lehn, G. Baum and
D. Fenske, Angew. Chem., Int. Ed. Engl., 1997, 36, 1842; (b)
A. M. Garcia, F. J. Romero-Salguero, D. M. Bassani, J.-M. Lehn,
G. Baum and D. Fenske, Chem.–Eur. J., 1999, 6, 1803; (c) M. Barboiu,
G. Vaughan, R. Graff and J.-M. Lehn, J. Am. Chem. Soc., 2003, 34,
10257; (d) S. T. Onions, A. M. Frankin, P. N. Horton, M. B. Hursthouse
and C. J. Matthews, Chem. Commun., 2003, 2864; (e) M. Ruben,
J.-M. Lehn and G. Vaughan, Chem. Commun., 2003, 1338; (f)
M. Ruben, J. Rojo, F. J. Romero-Salguero, L. H. Uppadine and
J.-M. Lehn, Angew. Chem., Int. Ed., 2004, 43, 3644.
11 (a) M. Sakamoto, N. Matsumoto and H. Okawa, Bull. Chem. Soc. Jpn.,
1991, 64, 691; (b) G. Chessa, G. Marangoni, B. Pitteri, V. Bertolasi,
V. Ferretti and G. Gilli, J. Chem. Soc., Dalton Trans., 1990, 915; (c)
E. C. Constable and J. M. Holmes, Inorg. Chim. Acta, 1987, 126, 187;
(d) G. Paolucci, G. Marangoni, G. Bandosi and D. A. Clemente,
J. Chem. Soc., Dalton Trans., 1980, 459; (e) G. Bandoli, D. A. Clemente,
G. Marangoni and G. Paolucci, J. Chem. Soc., Chem. Commun., 1978,
235; (f) B. Chiswell and D. S. Litster, Inorg. Chim. Acta, 1978, 29, 25; (g)
G. Paolucci and G. Marangoni, Inorg. Chim. Acta, 1977, 24, L5; (h)
D. Wester and G. J. Palenik, Inorg. Chem., 1976, 15, 755; (i) D. Wester
and G. J. Palenik, J. Chem. Soc., Chem. Commun., 1975, 74; (j)
J. D. Curry, M. A. Robinson and D. H. Busch, Inorg. Chem., 1967, 6,
1570.
We thank CONACyT de Me´xico for a predoctoral fellowship
(Juan Ram´ırez, registro 113226), Prof. Jack Harrowfield for
helpful discussions and Nathalie Zorn for mass spectrometry
analyses.
Notes and references
12 NMR data for ligand 1: 1H NMR (CDCl3, 400 MHz, reference: solvent
residual peak, d 7.24 ppm): 8.62 (d, J = 4.4 Hz, 2H), 8,58 (d, J = 7 Hz,
2H), 8.33 (d, J = 7.7 Hz, 2H), 8.08 (s, 2H), 7.79 (td, J = 7.3, 1.5 Hz, 2H),
7.59–7.49 (m, 3H), 7.29 (ddd, J = 7.3, 4.8, 1.1 Hz, 2H), 3.88 (s, 6H) ppm;
13C NMR (CDCl3, 100 MHz, reference: solvent residual peak, d
77.2 ppm): 154.7, 149.4, 140.8, 136.5, 136.5, 132.4, 129.0, 128.6, 123.8,
120.6, 31.2 ppm. Bis(methylhydrazino)phenyltriazine (mp 155 uC) was
prepared in 40–50% yield by reflux of methylhydrazine (4 equiv.) with
2,4-dichloro-6-phenyltriazine (R. Menicagli, S. Samaritani and
V. Zucchelli, Tetrahedron, 2000, 56, 9705), in ethanol, during 2 h.
See: J.-L. Schmitt, PhD Thesis, Universite´ Louis Pasteur, Strasbourg,
2004.
˚
{ Crystallographic data (T = 173 K, radiation Mo-Ka = 0.71073 A).
[Co414](BF4)8: [Co4(C23H21N9)4](BF4)8?10CH3NO2; M = 3234.59; crystal
system: tetragonal; space group: P42/n (no. 86); a = 17.2360(4), c =
˚
3
24.4290(4) A; V = 7257.4(3) A ; Z = 2; Dc = 1.376 g cm23; m = 0.546 mm21
;
˚
F(000) = 2964; 1.5u ¡ h ¡ 30.0u; hkl limits: 224/24, 217/17, 227/34;
number of data measured: 19072; number of data with I . 2s(I): 6475;
R = 0.1225. [Co(CH3CN)21](ClO4)2: [Co(CH3CN)2(C23H21N9)](ClO4)2;
M = 763.43; crystal system: monoclinic; space group: C2/c (no. 15); a =
3
˚
˚
15.542(4), b = 16.699(4), c = 13.539(3) A; b = 112.93(2)u; V = 3236.2(14) A ;
Z = 4; Dc = 1.567 g cm23; m = 0.762 mm21; F(000) = 1564; 2.1u ¡ h ¡
27.5u; hkl limits: 0/20,0/21,17/16; number of data measured: 3679; number
of data with I . 2s(I): 2528; R = 0.0488. CCDC 609649 and 609650. For
crystallographic data in CIF or other electronic format see DOI: 10.1039/
b612222a
13 (a) ES-MS for [Co1](ClO4)2: a peak corresponding to [Co1]2+ (m/z calc.
for [CoC23H21N9]2+: 241.0620, found: 241.0624); (b) ES-MS for
[Co414](ClO4)8: peaks corresponding to {[Co414](ClO4)6}2+ (m/z calc.
2+
for [Co4C92H84N36Cl6O24
] : 1263.0945, found: 1263.0826),
1 (a) J.-M. Lehn, Supramolecular Chemistry – Concepts and Perspectives,
VCH, Weinheim, 1995; (b) Comprehensive Supramolecular Chemistry,
Pergamon Press, Oxford, 1996; (c) J. W. Steed and J. L. Atwood,
Supramolecular Chemistry, Wiley, Chichester, 2000; (d) H.-J. Schneider
and A. Yatsimirsky, Principles and Methods in Supramolecular
Chemistry, Wiley, Chichester, 1999; (e) Supramolecular Materials and
Technologies, ed. D. N. Reinhoudt, Wiley, New York, 1999; (f) P. Cragg,
{[Co414](ClO4)5}3+ (m/z calc. for [Co4C92H84N36Cl5O20]3+: 808.4137,
found: 808.4103), {[Co414](ClO4)4}4+ (m/z calc. for
[Co4C92H84N36Cl4O16]4+: 581.5731, found: 581.5747).
14 (a) S. M. Socol and J. G. Verkade, Inorg. Chem., 1986, 25, 2658; (b)
J. Selbin, W. E. Bull and L. H. Holmes, J. Inorg. Nucl. Chem., 1961, 16,
219.
This journal is ß The Royal Society of Chemistry 2007
Chem. Commun., 2007, 237–239 | 239